https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66152
--- Comment #1 from SztfG at yandex dot ru ---
If array of char is initialized using string, gcc can use larger mov
instruction, like movabsq, movq, movl etc. but not movdqa, movaps or other xmm
But if zero byte appears in string, compiler always create a separate array and
copy it to stack, using various mov instruction, except xmm-based
void bar(void)
{
char a[4] = "\x00\x02\x03\x04";
foo(a);
}
produces
.LC0:
.string ""
.string "\002\003\004"
bar:
subq $24, %rsp
movl .LC0(%rip), %eax
movq %rsp, %rdi
movl %eax, (%rsp)
call foo
addq $24, %rsp
ret
